These are people with a few million in assets. Enough to retire comfortably. These are not the "Power Elite". At least, there is no evidence that these people are "Ultra-Wealthy", only that they have reached a certain threshold that the US Govt keeps track of them. And it's peaked at around 7,000 persons per year. Hardly a tidal wave of capital flight.
Have you considered that this story was titled in such a way to elicit an emotional response?